1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.log4j.util;
19
20 /***
21 * This class switches MDC values into the order
22 * (unreasonably) expected by the witness files.
23 */
24 public class MDCOrderFilter implements Filter {
25
26 /***
27 * Unexpected orders of keys.
28 * Note expected values are "va-one-one" and "va-one-two".
29 */
30 private static final String[] patterns =
31 new String[] {
32 "{key2,va12}{key1,va11}",
33 "{key2,value2}{key1,value1}"
34 };
35
36 /***
37 * Replacement values.
38 */
39 private static final String[] replacements =
40 new String[] {
41 "{key1,va11}{key2,va12}",
42 "{key1,value1}{key2,value2}"
43 };
44
45 /***
46 * Switch order of MDC keys when not in expected order.
47 */
48 public String filter(final String in) {
49 if (in == null) {
50 return null;
51 }
52
53 for(int i = 0; i < patterns.length; i++) {
54 int ipos = in.indexOf(patterns[i]);
55 if (ipos >= 1) {
56 return in.substring(0, ipos)
57 + replacements[i]
58 + in.substring(ipos + patterns[i].length());
59 }
60 }
61 return in;
62 }
63 }